The present invention relates to Chinese snacks which undergo a less change in eating texture and are capable of maintaining the excellent fresh eating texture. More specifically, the invention pertains to Chinese snacks which are capable of maintaining the fresh eating texture even after heating for cooking, storing in the frozen form, thawing upon selling, storing the thawed product for many hours or re-heating upon eating, by forming, between the filling and the dumpling skin of the snacks, a proteinic adhesive layer with which transglutaminase has reacted. Incidentally, at supermarkets or convenience stores, Chinese snacks which have been delivered thereat in the frozen form, are usually sold after thawing or cooking and then storing at room temperature or in a refrigerator, and purchasers heat them again upon eating. Of course, it is possible for a purchaser to heat the frozen Chinese snacks directly to a temperature suited for eating with a microwave oven or the like.
Many kinds of Chinese snacks require a heating step for making. Chinese snacks in the frozen form which have recently shown a steady increase on the market require, in addition thereto, re-heating in a microwave oven or the like upon thawing (at the stores as described above) or eating.
During such heating (step) or thawing step, or further, during storage after thawing, or the like, however, dripping becomes a problem. This dripping induces, in turn, various problems. Described specifically, dripping is accompanied with outflow of nutrients or components relating to the taste. In addition, since the dumpling skin portion of the Chinese snacks is swollen with water or oils and fats flowing out from their filling, not only eating texture but also their appearance is deteriorated. Moreover, owing to this outflow of water or oils and fats, the filling loses its juicy texture and becomes hard, and crumbling. Such a change in the eating texture and the like caused by dripping at the dumpling skin portion or filling has markedly deteriorated the preference for Chinese snacks. Upon storage at room temperature or in a refrigerator after cooking, or heating in a microwave oven upon eating, water transfer from the filling to the skin portion proceeds, resulting in a further deterioration in appearance and eating texture.
It is the common practice to add extra water or oils and fats to the filling in order to prevent a deterioration in the eating texture of the filling, in other words, to maintain juicy texture of the filling. An increase in the amount of water or oils and fats softens the food, thereby deteriorating moldability or formability. It also causes problems such as an increase in the amount of dripping during a heating step for sterilization or cooking, or during a thawing step for selling, and also an increase in the transfer amount of water from the filling to the skin portion upon storage at room temperature or in a refrigerator or heating in a microwave oven, leading to acceleration of a deterioration in the appearance of the skin portion or eating texture.
Technology has been reported to supplement the juicy texture of the filling by adding thereto a polysaccharide gel (Japanese Patent Application Laid-Open (Kokai) No. Hei 2-145157) or dry mashed potato and/or gellan gum gel (Japanese Patent Application Laid-Open (Kokai) No. Hei 8-317780). Although such techniques bring about some effects for improving the juicy texture of the filling just after cooking, the improved texture does not last long and moreover, the eating texture at the skin portion is, on the contrary, deteriorated by the addition.
Technical developments have so far been conducted for preventing a deterioration in the appearance or eating texture of the skin portion due to the transfer of water and the like from the filling. For example, reported are techniques for reducing the dripping amount from the filling by relaxing thawing conditions of frozen beef (Japanese Patent Application Laid-Open (Kokai) No. Hei 1-181740), spraying a high-temperature oil on the surface of a vegetable, thereby forming its film thereover (Japanese Patent Application Laid-Open (Kokai) No. Hei 2-238860), removing dripping from meat which appears upon heating, by using a water absorptive material (Japanese Patent Application Laid-Open (Kokai) No. Hei 4-211325), or the like. According to these techniques, however, deteriorations in the appearance and eating texture of the skin portion can be suppressed, but they have a difficulty in maintaining the juicy texture of the filling.
A method wherein transglutaminase is used, is also proposed. Described specifically, reported as a method for making transglutaminase react with the surface or skin used for the dumpling skin portion of Chinese snacks are a method wherein transglutaminase is kneaded into noodles (Japanese Patent Application Laid-Open (Kokai) No. Hei 6-14733, Japanese Patent Application Laid-Open (Kokai) No. Hei 6-225717, Japanese Patent Application Laid-Open (Kokai) No. Hei 9-28334, and the like), a method wherein noodles are dipped in a transglutaminase solution (Japanese Patent No. 2749363), a method wherein noodles are dusted or scattered with a powdery transglutaminase preparation (Japanese Patent Application Laid-Open (Kokai) No. Hei 11-9209), and the like. According to the above-described methods, however, noodles are only reacted with by transglutaminase. The methods can be recognized to be slightly effective in preventing swelling of the skin portion, but are not recognized at all to be effective in retaining juicy texture of the filling.
As has been described above, it is very difficult to maintain, for many hours, the fresh appearance and eating texture of the skin portion and also the juicy texture of the filling, and the existing techniques cannot attain this.
[Problems to be Solved by the Invention]
Based on the background of the above-described prior arts, it is an object of the present invention to provide Chinese snacks which undergo a less change in eating texture and have a fresh texture maintained both at the skin portion and filling even for many hours after cooking, after thawing, or the like.
[Means for Solving the Problems]
With a view to overcoming the above-described problems, the present inventors have carried out an extensive investigation. As a result, it has been found that fresh, juicy texture of Chinese snacks can be maintained even after thawing when they are products frozen after cooking (frozen food), after heating (in a microwave oven) upon eating, or the like, by forming, between the filling and the dumpling skin portion, a proteinic adhesive layer with which transglutaminase has reacted. Based on such findings, the present invention has been completed.
Accordingly, the present invention relates to Chinese snacks having a proteinic adhesive layer with which transglutaminase has reacted, formed between the filling and the dumpling skin thereof, and uncooked Chinese snacks half-made in such that a proteinic adhesive layer can be formed between the filling and the dumpling skin thereof by the action of transglutaminase, as well as such Chinese snacks in the frozen form (frozen foods).